Import script for Woocommerce and variable products.

import.php

<?php require __DIR__ . '/../htdocs/wp-load.php';

// Decode products.json into an array of products.
$products = json_decode( file_get_contents( __DIR__ . '/products.json' ), true );

// Now we want to loop through and create the top-level product.
foreach ( $products as $product ) {

    /**
     * A product is just a Wordpress post with a different 'post_type',
     * therefore we can use Wordpress' built-in functionality of
     * wp_insert_post for the creation of our products, the bare minimum a post
     * needs to get created is 'post_title' and 'post_type'
     *
     * @link(https://developer.wordpress.org/reference/functions/wp_insert_post)
     */

    $args = array(
        'post_title' => $product['title'],
        'post_content' => $product['description'],
        'post_status' => 'publish',
        'post_type' => 'product'
    );

    $product_id = wp_insert_post( $args );

    /*
     * Set the product to a variable product, if you want a simple product,
     * then set the value to 'simple'
     */

    wp_set_object_terms( $product_id, 'variable', 'product_type' );

    /*
     * We need to update the meta data for the top-level product before we
     * create any variations. It's pretty self-explanatory, play about with
     * these to understand what meta data changes.
     */

    update_post_meta( $product_id, '_sku', $product['sku'] );

    update_post_meta( $product_id, '_visibility', 'visible' );
    update_post_meta( $product_id, '_stock_status', 'instock' );
    update_post_meta( $product_id, '_sold_individually', '' );
    update_post_meta( $product_id, '_manage_stock', 'no' );
    update_post_meta( $product_id, '_stock', '' );

    update_post_meta( $product_id, '_downloadable', 'no' );
    update_post_meta( $product_id, '_virtual', 'no' );

    update_post_meta( $product_id, '_price', $product['price'] );
    update_post_meta( $product_id, '_regular_price', $product['price'] );

    update_post_meta( $product_id, '_sale_price', '' );
    update_post_meta( $product_id, '_sale_price_dates_from', '' );
    update_post_meta( $product_id, '_sale_price_dates_to', '' );

    update_post_meta( $product_id, 'total_sales', '0' );

    update_post_meta( $product_id, '_purchase_note', '' );
    update_post_meta( $product_id, '_featured', 'no' );
    update_post_meta( $product_id, '_backorders', 'no' );

    /**
     * $attributes_collection will build up into an array simliar to this:
     * It may contain duplication.
     * ["Size" => ["XL", "L", "M", "S"], "Colour" => ["Blue"]]
     *
     * @var array $attributes_collection
     */

    $attributes_collection = array();

    /**
     * A multi-dimensional array containing the Wordpress data needed to insert
     * custom attributes for a product.
     *
     * See further down for an example of the array.
     *
     * @var array $product_attributes
     */

    $product_attributes = array();


    /**
     * Building up the $attributes_collection array.
     */
    foreach ( $product['variations'] as $variation ) {

        // Loop through the variations' attributes.
        foreach ( $variation['attributes'] as $key => $value ) {

            if ( ! array_key_exists( $key, $attributes_collection ) ) {
                $attributes_collection[$key] = array();
            }

            $attributes_collection[$key][] = $value;

        }

    }

    /*
     * Loop through the array we just built, and create a Wordpress ready
     * multi-dimensional array.
     */
    foreach ( $attributes_collection as $attribute_name => $attributes ) {

        // Remove any duplication from the attributes.
        $attributes = array_unique( $attributes );

        // Create a wordpress ready name, this will convert to lowercase and,
        // strip out spaces for _ and convert to lowercase. It's often used for
        // slugs.
        $sanitized_attribute_name = sanitize_title( $attribute_name );

        /*
         * The array key should be a sanitized version of the NAME of your attribute.
         * Use sanitize_title
         *
         * 'name'         = Unsanitized name for the attribute, e.g. Colour, Size
         * 'value'        = Imploded array of attributes, similiar to that of which
         *                  you would populate the Woocommerce backend with e.g. XL|L|M|S
         * 'position'     = Order of the attribute.
         * 'is_visible'   = Whether it should be visible on the front-end.
         * 'is_variation' = Whether it could be used for product variations
         * 'is_taxonomy'  = Is the attribute based off a taxonomy.
         *
         * 0 = FALSE, 1 = TRUE
         */
        $product_attributes[$sanitized_attribute_name] = array(
            'name'          => $attribute_name,
            'value'         => implode( '|', $attributes ),
            'position'      => 0,
            'is_visible'    => 1,
            'is_variation'  => 1,
            'is_taxonomy'   => 0
        );

    }

    /*
     * Update _product_attributes post meta to contain a serialized array of our
     * product attributes.
     */
    update_post_meta( $product_id, '_product_attributes', $product_attributes );


    foreach ( $product['variations'] as $variation ) {

        // Create a different title based off the product attributes,
        // You could also set this within your array get get it from a different
        // data source.
        $variation_title = $product['title'];
        foreach ( $variation['attributes'] as $attribute ) {
            $variation_title .= ' - ' . $attribute;
        }

        /*
         * Like we did when creating the top-level product, only this time with
         * a post_type of 'product_variation'
         */
        $args = array(
            'post_title'    => $variation_title,
            'post_status'   => 'publish',
            'post_type'     => 'product_variation',
            'post_parent'   => $product_id
        );

        $variation_id = wp_insert_post( $args );

        /**
         * Loop through the attributes for the product and insert post meta to
         * update the attribute for the product.
         */
        foreach ( $variation['attributes'] as $attribute_name => $attribute ) {

            $sanitized_attribute_name = sanitize_title( $attribute_name );

            // When creating post_meta for the attributes, prefix the
            // sanitized attribute name with 'attribute_'
            $attribute_key = 'attribute_' . $sanitized_attribute_name;

            // Update the post meta from the attribute.
            update_post_meta( $variation_id, $attribute_key, $attribute );

        }

        /*
         * Update the SKU from the data source, as well as the prices.
         */
        update_post_meta( $variation_id, '_sku', $variation['sku'] );
        update_post_meta( $variation_id, '_price', $product['price'] );
        update_post_meta( $variation_id, '_regular_price', $product['price'] );

    }

}

products.json

[{
    "title": "T-Shirt",
    "description": "A t-shirt fit for all occasions.",
    "price": 20.00,
    "sku": "TSHIRT",
    "variations": [{
        "attributes": {
            "Colour": "Blue",
            "Size": "XL"
        },
        "sku": "TSHIRTXLB"
    }, {
        "attributes": {
            "Colour": "Blue",
            "Size": "L"
        },
        "sku": "TSHIRTLB"
    }, {
        "attributes": {
            "Colour": "Blue",
            "Size": "M"
        },
        "sku": "TSHIRTMB"
    }, {
        "attributes": {
            "Colour": "Blue",
            "Size": "S"
        },
        "sku": "TSHIRTSB"
    }]
}]